JPH02307091A - Stage mechanism - Google Patents

Abstract

PURPOSE:To prevent the stage mechanism from vibrating in its movement by providing a balance part which moves corresponding to the movement of a stage, and holding the gravity center position of the stage mechanism invariably constant and canceling its moment of inertia. CONSTITUTION:An external screw part 5a and an internal screw part 4b are cut in a main driving shaft 4 at the same pitch in opposite directions. Then the internal screw part 5b is engaged with the external screw part 4a and the external screw part 6a of the driving shaft 6 of a balance part is engaged threadably with the internal screw part 4b. Here, when a driving part 3 rotates the main driving shaft 4, the stage 5 moves in a specific direction and the balance part driving shaft 6 and a balance part 7 move in opposite directions. Therefore, the center of gravity of the stage mechanism 1 is held at a constant position at all times and the moment of inertia generated in the stage mechanism 1 is canceled, so vibration in the stage movement can be precluded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a stage mechanism used as a step-driven movable stage in an exposure apparatus of a semiconductor manufacturing apparatus or the like.

<Prior Art> FIG. 3 shows a conventional stage mechanism used in exposure equipment for semiconductor devices.

The stage mechanism 21 has a drive unit 3 fixed to the base 2J. The drive section 3 is provided with a drive shaft 22 so as to be freely drivable. A stage 23 is attached to the drive shaft 22. The stage 23 is slidably provided on the base 2.

Further, the base 2 is usually installed on a vibration isolator 11 in order to reduce the influence of vibration from the installation surface.

Next, the operation of the stage mechanism 21 will be explained.

First, the drive section 3 or the drive shaft 22 is driven in the axial direction. Accordingly, the stage 23 slides on the base 2.

A case where the stage mechanism 21 described above is used in a stepper of a semiconductor device will be explained with reference to FIG.

Typically, the stepper 20 is provided with an exposure optical system 15 that includes an exposure illumination section, a condenser lens section, a reticle installation section, and a reduction lens section. The exposure optical system 15 is fixed to an arm 16.

The arm J6 is fixed on the base 2 of the stage mechanism 21.

Further, a semiconductor wafer 30 is placed on the stage 23 of the stage mechanism 21.

A reticle pattern is exposed onto the semiconductor wafer 30 each time the stage 23 is driven step by step.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional technology, (a) as the stage moves, the center of gravity of the stage mechanism moves, which causes the base supported by the vibration isolator to lose its balance, causing the stage mechanism to or cause vibration.

When the stage moves, acceleration is generated on the stage, so a moment of inertia is generated in the drive unit via the drive shaft in the direction of movement of the stage or in the opposite direction, which tends to rotate the stage mechanism. This causes the stage mechanism to vibrate.

When such a conventional stage mechanism is used in an exposure device of semiconductor manufacturing equipment, especially a stepper, the positioning accuracy decreases, causing pitch deviation and chip rotation, and the focusing accuracy decreases, resulting in poor resolution. Therefore, there has been a problem in that the yield of exposed semiconductor devices is reduced.

Means for Solving the Problems> The present invention has been made to solve the above problems, and an object of the present invention is to provide a stage mechanism that prevents vibrations that occur when the stage moves.

In other words, the stage and the balance section move in the opposite direction to the direction in which the center of gravity of the stage moves, and the center of gravity formed by the stage, the balance section, and the balance section drive shaft is always kept at a constant position, and the movement of the stage moves the center of gravity of the stage. This mechanism is characterized by the provision of a balance section that moves at a predetermined acceleration that cancels out the moment of inertia generated in the mechanism.

(Function) The stage mechanism described above is provided with a balance section that moves in response to the movement of the stage, so that the center of gravity formed by the stage, the balance section drive shaft, and the balance section changes in response to the movement of the center of gravity of the stage. The center of gravity, which is formed by the balance part drive shaft and the balance part, moves and is always kept at a constant position.

Therefore, the center of gravity of the stage mechanism is always kept at a constant position.

In addition, the mass of the stage and the sum of the mass of the balance part drive shaft and balance part are set to be the same mass, and the absolute value of the acceleration of the stage is set so that the balance part drive shaft and the balance part do not meet. The balance section is set equal to , and the balance section is moved in the opposite direction to the moving direction of the stage together with the balance section drive shaft to cancel out the moment of inertia generated in the stage mechanism.

Therefore, vibrations caused by the movement of the stage are prevented.

<Example> Embodiments of the present invention will be described based on the drawings.

In the stage mechanism 1 shown in FIG. 1, a drive section 3 is fixed on a base 2 provided with a vibration isolator 11.

The drive portion 3 is rotatably provided with a main drive shaft 4 having a male threaded portion 4a and a female threaded portion 4b. The male threaded portion 4a and the female threaded portion 4b have the same pitch, and the winding directions of the threads are opposite to each other.
The axes of each should be aligned.

Furthermore, a stage 5 is slidably provided on the base 2.

The stage 5 is formed with a female threaded portion 5b that is screwed into the male threaded portion 4a of the main drive shaft 4. And stage 5
is slid in the direction of the axis X of the main drive shaft 4 as the main drive shaft 4 rotates. Also, the center of gravity Gs of the stage 5 is the main drive shaft 4.
It is aligned with the axis X of .

On the other hand, the main drive shaft 4 is provided with a balance drive shaft 6 having a male threaded portion 6a that is screwed into a female threaded portion 4b.

The axis X° of the balance drive shaft 6 is aligned with the axis X of the main drive shaft 4.

The balance part drive shaft 6 moves in the axis x direction in conjunction with the rotation of the main drive shaft 4.

A balance part 7 is attached to the tip of the balance part drive shaft 6 and inside the stage 5, and is slidably provided on the base 2. In addition, the center of gravity G [l is the axis X of the main drive shaft formed by the balance part 7 and the balance part drive shaft 6
It should match.

Next, the operation of the stage mechanism I having the above configuration will be explained.

When the main drive shaft 4 is rotated by the drive unit 3, the stage 5 moves in a predetermined direction.

At this time, the balance part drive shaft 6 moves in the opposite direction to the moving direction of the stage 5. Further, the absolute value of the acceleration of the balance portion drive shaft 6 is equal to the absolute value of the acceleration of the stage 5.

Accordingly, the balance section 7 also moves together with the balance section drive shaft 6.

In this way, the center of gravity G formed by the stage 5, the balance part drive shaft 6, and the balance part 7 is always kept constant, and the moment of inertia generated by the movement of the stage 5 is canceled out.

A case in which the stage mechanism 1 described above is used in a stepper of a semiconductor manufacturing apparatus will be explained with reference to FIG.

Usually, the stepper 10 is provided with an exposure optical system 15 that includes an exposure illumination section, a condenser lens section, a reticle installation section, and a reduction lens section. The exposure optical system 15 is fixed to an arm 16.

The arm 16 is fixedly mounted on the base 2 of the stage mechanism 1.

Further, a semiconductor wafer 30 is placed on the stage 5.

A reticle pattern is exposed onto the semiconductor wafer 30 each time the stage 5 is driven step by step.

At this time, since no moment of inertia is generated to rotate the stage mechanism 1, the stage mechanism 1 eliminates vibrations caused by the moment of inertia.

Therefore, the arm 16 no longer vibrates, and the exposure optical system 15
or stably fixed.

Therefore, the stage mechanism 1 prevents the pitch deviation of the reticle pattern exposed by the stepper 10.

This eliminates chip rotation, etc., and also eliminates poor resolution due to defocus.

<Effects of the Invention> As explained above, according to the present invention, since a balance section that moves in response to the movement of the stage is provided, the center of gravity of the stage mechanism can always be kept at a constant position. At the same time, the moment of inertia that tries to rotate the stage mechanism can be canceled out.

Therefore, vibration of the stage mechanism that occurs when the stage moves can be prevented, and when used as a movable stage in exposure equipment of semiconductor manufacturing equipment, excellent exposure is achieved without pitch deviation, chip rotation, etc., and without defocusing. It is possible to form a pattern, and the yield of exposed semiconductor devices can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic partially cutaway front view explaining the present invention in detail. FIG. 2 is a front view explaining a stepper provided with the stage mechanism in FIG. 1. FIG. 3 is a conventional stage mechanism. FIG. 4 is a front view illustrating a stepper provided with the stage mechanism shown in FIG. 3. ■...Stage mechanism, 2...Base. 3... Drive unit, 4... Main drive shaft. 5... Stage, 6... Balance part drive shaft. 7... Balance part, 4a, 6a... Male screw part. 4b, 5b...Female screw part. G5: Center of gravity of the main stage. X: Axis of main drive shaft. X'...Axis of balance unit drive shaft.

Claims (1)

[Claims] A base, a drive section provided on the base, a main drive shaft driven by the drive section, and a main drive shaft attached to the main drive shaft and slidably provided on the base. It is composed of a stage, a balance part drive shaft provided so as to be interlocked with the main drive shaft, and a balance part attached to the balance part drive shaft, and the axis of the balance part drive shaft is aligned with the axis of the main drive shaft. and each axis is set horizontally with respect to the moving surface of the stage, the drive direction of the balance part drive shaft is set in the opposite direction to the drive direction of the main drive shaft, and the center of gravity of the stage and the balance The center of gravity formed by the balance section and the balance section drive shaft is aligned with the axis of the main drive shaft, and the absolute value of the acceleration generated at the center of gravity of the stage and the acceleration of the center of gravity formed between the balance section and the balance section drive shaft are determined. A stage mechanism characterized in that the absolute values are set to be the same, and the mass of the stage and the sum of the mass of the balance section and the balance section drive shaft are set to be the same mass.